Altered biomechanical strategies and medio-lateral control of the knee represent incomplete recovery of individuals with injury during single leg hop

Abstract

Anterior cruciate ligament (ACL) injury can result in failure to return to pre-injury activity levels and future osteoarthritis predisposition. Single leg hop is used in late rehabilitation to evaluate recovery and inform treatment but biomechanical understanding of this activity is insufficient.This study investigated single leg hop for distance aiming to evaluate if ACL patients had recovered: (1) landing strategies and (2) medio-lateral knee control. We hypothesized that patients with reconstructive surgery (ACLR) would have more similar landing strategies and knee control to healthy controls than patients treated conservatively (ACLD).16 ACLD and 23 ACLR subjects were compared to 20 healthy controls (CONT). Kinematic and ground reaction force data were collected while subjects hopped their maximum distance. The main output parameters were hop distance, peak knee flexor angles and extensor moments and Fluency (a measure introduced to represent medio-lateral knee control). Statistical differences between ACL and control groups were analyzed using a general linear model univariate analysis, with COM velocity prior to landing as covariate.Hop distance was the smallest for ACLD and largest for CONT (p<0.001; ACLD 57.1±14.1; ACLR 75.1±17.8; CONT 77.7±14.07% height). ACLR used a similar kinematic strategy to CONT, but had a reduced peak knee extensor moment (p<0.001; ACLD 0.32±0.14; ACLR 0.31±0.16; CONT 0.42±0.13 BW.height). Fluency was reduced in both ACLD and ACLR (p=0.006; ACLD 0.13±0.34; ACLR 0.14±0.34; CONT 0.17±0.41 s).Clinical practice uses hopping distance to evaluate ACL patients' recovery. This study demonstrated that aspects such as movement strategies and knee control need to be evaluated.

Whole Body Coordination and Knee Movement Control During Five Rehabilitation Exercises

“…The knee axes were aligned using the anatomical calibration trial. In some trials the trunk and hips flexed as such that the markers on the left and right anterior superior iliac crests (LASI and RASI) were occluded; these gaps were filled using the data of the LILC and RILC markers in a custom written programme in Vicon BodyBuilder for T=1/f) was used so that a larger value agreed with a more fluent movement [13].…”

“…For example, poor knee control in the frontal plane during hopping has been associated with increased risk of anterior cruciate ligament (ACL) injury [8] and increased medial knee loading in the frontal plane during walking has been associated with development of osteoarthritis [9]. Therefore, knee movement assessment in the frontal plane is routine clinical practice [10] and improvement of knee control in the frontal plane is an important objective during functional exercises which will focus on neutral alignment of the knee [8,[10][11], movement fluency [12][13][14] and displacement variability [15].…”

“…Fluency in studies of medio-lateral knee control [13][14] was defined as the number of times per second the velocity of the knee position in the frontal plane crossed zero calculated by a method adapted from Smeulders et al [12]. Roos et al [13] found that following landing from a hop knee frontal plane movement fluency was significantly different between three groups; knee movement was least fluent in patients with ACL deficiency due to injury (ACLD); patients with anterior cruciate ligament reconstruction (ACLR) were intermediate; and knee movement was most fluent in healthy control subjects.…”

“…Roos et al [13] found that following landing from a hop knee frontal plane movement fluency was significantly different between three groups; knee movement was least fluent in patients with ACL deficiency due to injury (ACLD); patients with anterior cruciate ligament reconstruction (ACLR) were intermediate; and knee movement was most fluent in healthy control subjects. Panos et al [18] found similar results when asking people with ACL injury to perform drop landing tasks.…”

Mapping current research trends on anterior cruciate ligament injury risk against the existing evidence: In vivo biomechanical risk factors

“…The other eleven studies investigated biomechanical variables in the context of stability and postural control [37][38][39][40], gait [41], vision [42], limb asymmetry [43], walk and jog patterns [44], gender differences [45], as well as neuromuscular aspects [46]. Landing strategies and medio-lateral control of the ACLD and ACLR patients were also investigated by Roos et al [47] and found that these groups had not fully recovered.…”